We propose to study a newly discovered fluoride-calcium-phosphate (FCaP) complex that allows preparation of solution compositions simultaneously containing all there tooth mineral ions: fluoride, calcium, and phosphate, without precipitation The FCaP solutions can be triggered to precipitate phosphate-contaminated calcium fluoride (hereafter abbreviated as CaF2) alone or CaF2 and F-containing apatitic (F-Ap) minerals. Preliminary results showed the feasibility of using FCaP for developing higher efficacy F regimens without increasing the F dose, or with a lower F dose. In order to achieve this objective, it is necessary to obtain a better understanding of the FCaP complex itself. Specifically, what are the composition ranges in which stable FCaP can exist? What is the structure of FCaP, What are the factors that destabilize FCaP, leading to precipitation? We propose to conduct studies aimed at gaining insights into these questions through the following Aims: Aim 1 - Preparation and characterization of FCaP complex formed under a wide range of solution compositions. Aim 2 - Factors that destabilize FCaP complex leading to precipitation and characterization of the precipitation products. Aim 3 - Initial Evaluation of F deposition produced by FCaP complex solutions in an in vitro model. Successful outcome of the proposed research can open new frontiers of future research aimed at improving the anticaries efficacy of F while decreasing the F strength and is safer to used, especially for children. PUBLIC HEALTH RELEVANCE: We propose to study a newly discovered fluoride-calcium-phosphate (FCaP) complex that allows preparation of solution compositions that simultaneously contain desired levels of all there tooth mineral ions: fluoride, calcium, and phosphate, without precipitation. The FCaP solutions can be triggered to precipitate F reservoirs in the mouth. Successful outcome of the proposed research can lead to development of new ultra effective oral rinses, dentifrices, gels, and F-containing calcium phosphate remineralizing products with a lower F strength in the product, and therefore is safer to use.